Rotary paper-cutter knife structure

ABSTRACT

A rotary paper-cutter knife structure the knife blade of which is secured in a trough of a knife holder in the form of the revolver of a conventional paper-cutter machine. The knife is radially adjustable by means of a pusher having a ledge contacting the heel surface of the knife and having screw means extending therethrough and engaging the bottom surface of the trough. The knife blade is releasably clamped in the trough by means of wedges.

United States Patent Matthews 1 Nov. 21, 1972 [54] ROTARY PAPER-CUTTERKNIFE 2,751,006 6/1956 Lane ..83/674 STRUCTURE 2,735,488 2/1956 Andersonet al ..83/677 X 3,321,145 5/1967 Gorman- ..83/349 X [72] Invent gf'3,322,012 5/1967 Murray ..83/345 x 2,270,639 l/l942 Parks, Jr ..83/677[73] Assignee: Maxsou Automatic Machinery Company, Westerly, R I PrimaryExaminerJames M. Meister Filed Dec 1 1970 Attorney-Rines and Rines [21]Appl. No.2 93,978 [5 ABSTRACT A rotary paper-cutter knife structure theknife blade 52 us. C1 ..83/677, 83/700 of which is Secured in a troughof a knife holder in the I511 1nt.C1. ..B23d 25/12 form of the revolverof a conventional Paper-cutter 5s Field of Search ..83/677 674 345-348machine- The knife is radially adjustable by means 85/698406 a pusherhaving a ledge contacting the heel surface of the knife and having screwmeans extending therethrough and engaging the bottom surface of the [56]References cued trough. The knife blade is releasably clamped in theUNITED STATES PATENTS trough y means of Wedges- 2,660,242 1 1/ 1953 Lane..83/674 6 Claims, 3 Drawing Figures P'A'TE'N'TEDnnv 21 1912 3, 7.03 1

t] 3 INVENTOR.

Merton Lou/s Matthews Attorneys ROTARY PAPER-CUTTER KNIFE STRUCTUREBACKGROUND OF THE INVENTION.

1. Field of the Invention The invention is in the field represented bythe conventional rotary paper-cutter industry.

2. Description Of The Prior Art.

In paper cutters of this type, the knife blade is customarily held inplace by bolts passing through holes 1 in the blade. These bladesnormally have arrangements by which they can be adjusted for positioningof the cutting edge through push or pull screws or a combination of pushand pull screws. The push and pull screws may work on the blade itselfor on a carrying bar to which the blade is bolted.

The method of securing the cutting blade to the revolver with boltsresults in a number of undesirable effects, the most obvious and commonof which is an increase in difficulty of setting the knife resultingfrom localized force vectors of varying directions set up in the bladeby the holding bolts.

A second disadvantage occurs when blades are sharpened. If they are notheld in a fixture which duplicates the holding bolt locations of theactual revolver, a wave edge may result when the blade is secured bythese bolts and this must be overcome through manipulation of thepush-pull screws.

A third problem occurs during operation. The vibrations and shocksresulting from cutting loads tend to loosen or tighten the holding boltschanging the localized force vectors surrounding these bolts and causingthe blade to creep or lose its setting.

Another disadvantage results from the fixed position of the adjustingscrews along the length of the blade; because of this overcorrection andexcessive honing is often necessary if a minor nick occurs at a pointwhere the adjusting screws happen to have least effect because oflocation.

An object of the present invention is to improve upon the mounting ofknives of the above-described character.

A further object is to provide a knife structure that shall eliminatethe need for the use of the holes and bolt-head seats in the knife bladeand of the bolts that are mounted in those holes.

Another object is to provide a new and improved knife structure of theabove-described character the knife blade of which shall be effectivelywedge-locked against accidental removal from the revolver upon which itis mounted.

Still another object is to provide new and improved means for adjustingthe knife blade on the revolver upon which it is mounted.

Other and further objects will be explained hereinafter and will beparticularly pointed out in the appended claims.

SUMMARY OF THE INVENTION According to the invention, the knife blade ismounted in a small, longitudinally extending trough provided in thesurface of the revolver of the machine. The knife blade is adjustablysupported in the trough by pusher-part supports disposed adjacent to thebottom surface of the trough. Accidental removal of the blade from itstrough is prevented preferably by means of a wedge lock.

BRIEF DESCRIPTION OF THE DRAWINGS The invention will be described inconnection with the accompanying drawings, in which FIG. 1 is adiagrammatic elevation of a revolver cylinder upon which a knife bladeis mounted according to a preferred embodiment of the present invention;and

FIGS. 2 and 3 are sections taken upon the respective 0 lines 2-2 and 33of FIG. 1, upon a larger scale.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION A smallknife-receiving trough 2 is shown provided in the surface of aknife-blade holder, shown as a cylindrical revolver 4 of theabove-described type. The trough 2 may be constructed in any desiredmanner, as by milling of the conventional type. Though the revolver 4 isshown provided with only a single trough 2, it will be understood thatthe revolver may be provided with several such troughs 2, each receivinga knife.

The dimensions of the trough 2 will vary with the dimensions of theknife blade 5 that is to be received therein. Troughs 2 of dimensionsthree-fourths inch wide by three-fourths inch deep or 1 inch wide X 1inch deep have been used successfully,'but much smaller or largertroughs may also be used.

Though the trough 2 is shown diagrammatically extending longitudinallyof the cylinder of the revolver, it is usually cut on a true helixangle; as the cutter that mills the trough moves along linearly anduniformly, the revolver is uniformly rotated around its axis, the twomovements being in constant fixed ratio. By reason of this method ofcutting the trough, the blade 5 produces a common-type shear cut.

The trough 2 is provided with a bottom-wall surface 6 and two oppositelydisposed radial, but substantially parallel, side-wall surfaces 8 and10, substantially perpendicular to the bottom wall surface 6.

The side wall surfaces 8 and 10, as will hereinafter be more fullyexplained, need not, however, have this precise configuration; but, ifthey do, the oppositely disposed front and back surfaces 14 and 16 ofthe knife blade 5 are tapered with respect to each other, as shown. Theback side surface 16, for example, may be ground at an angle to thefront side surface 14 of between 2% and 7, but this angle is notcritical, and angles of 15 and 20 are permissible. Larger and smallerangles may also be used. The width of the bottom heel surface 34 of theknife 5 may be selected as desired; widths of three-sixteenths inch andfive-sixteenths inch have been used with excellent results. Thethickness of the heel and the angle of taper is determined, not by ademand of strength or rigidity of the blade but, rather, by the amountof clearance demanded between the revolver body 4 and the cutting edgeof the blade 5. This clearance is usually determined by the type ofmaterial being sheeted. Clearances of one-eighth inch to three-fourthsinch have been used successfully and greater or lesser clearances arefeasible. The choice of cutting clearance angle from the cutting edge tothe back side surface 16 of the knife will depend on the material to becut.

The blade 5 may be constituted of high-speed steel with a hardness of60-62 on Rockwell C Scale, but softer or harder blades of the same ordifferent material are also suitable.

The knife 5 is shown secured in the trough 2 by means of a plurality ofclamps 20. These clamps may be made of any desired material, such as atough hardenable steel, or even normal cold rolled steel with nosubsequent heat treatment.

The front side surface of this clamp' 20 is shown ground to the sameangle as that of the back side surface 16 of the knife, in order toenable these surfaces to be mounted in contact with each other.

ln the preferred embodiment of the invention, as illustrated, the clamp20 is constituted of one arm of a bifurcated resilient U-shaped memberthe other arm of which is shown at 22.

It is not essential, however, that the arms 20 and 22 be made in onepiece. Separate arms 20 and 22, not shown, may be used with equaleffectiveness, though they naturally lack the resiliency provided by thesmall neck 7 of the U.

The U-shaped member comprising the arms 20 and 22 is provided with acentrally disposed countersunk threaded cylindrical opening 24 forreceiving a correspondingly shaped clamp-expander screw 26. By the arms20 and 22 becomingthuspressed away from each other, the knife blade 5becomes wedge-locked against the surface 6 of the trough.

The invention may, however, be practiced without the wedging effectproduced by tapering the contacting surfaces of the knife blade 5 andthe clamp 20. Enough side thrust can be generated by the describedlocking expansion even if these contactingsurfaces of the knife blade 5and the clamp 20 are untapered. There is a remote possibility, however,with such untapered surfaces, that the blade might accidentally fly outof the trough if, for some reason, the expanding screw 26 should becomeloose. The tapered faces provide insurancc against this type of possibleaccident.

lt will also be understood that, even where the tapering is employed,the knife 5 may be untapered, and the taper may be provided, instead,upon one of the side surfaces 6 and 8 of the trough 2. In all thesecases, the knife blade 5 will become wedge-locked in the trough 2 byreason of the fact that portions of the clamp 20 and the knife surfacecontacting therewith are tapered with respect to one or both of thetrough side surfaces 10 and 8 in order to wedge-lock the knife 5 in thetrough 2.

The invention provides also for adjusting the position of the knifeblade 5 in the trough 2. To the attainment of this end, a plurality ofpusher-part knife supports 30 are disposed in the trough 2 adjacent tothe bottom surface 6 thereof. The pusher-part supports 30 may beadjusted up and down in the trough 2, away from and toward the bottomwall surface 6, by adjustment of set screws 32. The heel 34 of the knifeblade 5 contacts with projecting knife-supporting ledges 36 of thepusher-part supports 30. Adjustment of these pusherpart supports 30,therefore, will effect correspondingadjustment of the blade 5, towardand from the bottom wall 6 of the trough 2.

The pusher-part supports 30 are shown as alternating with, orintercalated between, the clamps 20, in wide spaces between the clamps,to enable wide lateral adjustment of the pushenpart supports. Closer andwider spacings of the pusher-part supports have been used withsatisfactory results. Some of the advantages of the invention are:

A. A minimum amount of metal needs to be removed from the revolver,which affords the following advantages:

Maximum strength and rigidity of revolver for a given diameter. Theentire circumference of the revolver can b machined smooth for optimumaerodynamic design, and the use of covers or fill-in pieces is notnecessary.

. Simplicity and ease of machining the revolver. The ease with which amulti-bladed revolver can be fabricated even with small-diameterrevolvers. The entire knife mounting requires so little length of arc ofcircumference that many holding troughs can be machined into a singlerevolver.

. Base with which a multi shear angle revolver can B. Knife is easier toinstall and adjust because of the following: I

Knife is seated or wedged against a surface machined true to axis ofrevolver. The only movement possible is in one plane at to revolveraxis.

. Knife blade can be of small cross section as rigidity may be obtainedfrom method of mounting thereby making it easier to deflect to conformto helix angle and requiring less force to deflect it for setting.

. Adjustment pushers shown on print can be moved parallel to axis ofrevolver between clamps allowing technician setting blade to obtainmovement at position desired.

. Knife does not tend to walk or move during final tightening action. I

. Adjustment of one point in blade does not cause movement at adifferent point further along the blade. A knife blade, constructed andmounted as above described, need not be itself rigid, it becomesinherently endowed with rigidity and stability.

C. Knife maintains set and sharpness longer requiring fewer adjustmentsbecause:

. Method of mounting allows maximum rigidity of revolver for a givenrevolver diameter, reducing vibration which destroys edge.

. Greater rigidity results in less deflection under cutting load.

. Because of the wedge locking action unit does,

holding bolts do not tend to loosen under impact loading allowing bladeto walk" out of setting.

D. Because the cutting edge of the blade is wedged against the milledtrough the cut line must be as straight and true as the slot itself andproviding the slot is true and bed or stationary knife are true it isimpossible to set the knife in such a manner that a concave or convexcut line is obtained.

E. If the slot is machined true it is impossible to vary the front rake"or clearance angle through improper setting and knife loading willthereby remain constant through entire length of cut.

F. Knife is safer to operate at higher speeds. Because of the wedgeangles it is impossible for the knife to move outward throughcentrifical force. The possibility of hooking the blade against thebedknife blade is lessened.

G. With this type of knife mounting it is feasible to increase shearangle of knife trough to the point that a diagonal cut is obtained.

Further modifications will occur to persons skilled in the art and allsuch are considered to fall within the spirit and scope of the presentinvention, as defined in the appended claims.

lclaim:

1. A knife structure comprising a knife holder having a trough providedwith a bottom surface and two side surfaces, a pusher-part knife supportdisposed in the trough and having a ledge adjacent to the bottomsurface, a knife in the trough having a heel surface contacting with theledge of the pusher-part support to support the knife in the trough, thepusher-part support having screw means extending therethrough andengaging the bottom surface of the trough for adjusting said ledgetoward and from the bottom surface of the trough to provide forcorresponding adjustment of the heel surface in contact with said ledge,and clamp means for pressing said knife against one side surface of thetrough to secure the knife in the trough 2. A knife structure comprisinga cylindrical revolver having a trough provided with a bottom surfaceand two side surfaces extending longitudinally of the cylinder, apusher-part knife support disposed in the trough and having a ledgeadjacent to the bottom surface, a knife having a heel surface contactingwith the ledge of the pusher-part support to support the knife in thetrough and two side surfaces one of which contacts with one of thetrough side surfaces, the pusher-part support having screw meansextending therethrough and engaging the bottom surface of the trough foradjusting said ledge toward and from the bottom surface of the trough toprovide for corresponding adjustment of the heel surface in contact withsaid ledge, a clamp in the trough having two oppositely disposedsurfaces one of which contacts with the other knife surface, and meansengaging the other oppositely disposed surface of the clamp to securethe clamp in the trough in order to secure the knife in the trough.

3. A knife structure comprising a cylindrical revolver having a troughprovided with a bottom surface and two side surfaces extendinglongitudinally of the cylinder, a plurality of pusher-part knifesupports disposed in the trough and each having a ledge adjacent to thebottom surface, a knife having a heel surface contacting with the ledgesof the pusher-part supports to support the knife in the trough and twoside surfaces one of which contacts with one of the trough sidesurfaces, the pusher-part supports having screw means extendingtherethrough and engaging the bottom surface of the trough for adjustingsaid ledges toward and from the bottom surface of the trough to providefor corresponding adjustment of the portions of the heel surfacecontacting therewith, a plurality of clamps in the trough each havingtwo oppositely disposed surfaces one of which contacts with the otherknife side surface, and means engaging the other oppositely disposedside surfaces of the clamps to secure the clamps in the trough in orderto secure the knife in the trough, the said one surface of the clampsand the portion of the knife side surface in contact therewith beingtapered with respect to one of the trough side surfaces in order towedge the knife in the trough.

4. A knife structure as defined in claim 3 in which the pusher-partknife supports are separate from the clamps and are laterally adjustablein the trough.

5. A knife structure as defined in claim 1 in which the pusher-partknife support is separate from the clamp means and laterally adjustablein the trough.

6. A knife structure as defined in claim 2 in which the pusher-partknife support is separate from the clamp and is laterally adjustable inthe trough.

1. A knife structure comprising a knife holder having a trough providedwith a bottom surface and two side surfaces, a pusher-part knife supportdisposed in the trough and having a ledge adjacent to the bottomsurface, a knife in the trough having a heel surface contacting with theledge of the pusher-part support to support the knife in the trough, thepusher-part support having screw means extending therethrough andengaging the bottom surface of the trough for adjusting said ledgetoward and from the bottom surface of the trough to provide forcorresponding adjustment of the heel surface in contact with said ledge,and clamp means for pressing said knife against one side surface of thetrough to secure the knife in the trough .
 1. A knife structurecomprising a knife holder having a trough provided with a bottom surfaceand two side surfaces, a pusherpart knife support disposed in the troughand having a ledge adjacent to the bottom surface, a knife in the troughhaving a heel surface contacting with the ledge of the pusher-partsupport to support the knife in the trough, the pusher-part supporthaving screw means extending therethrough and engaging the bottomsurface of the trough for adjusting said ledge toward and from thebottom surface of the trough to provide for corresponding adjustment ofthe heel surface in contact with said ledge, and clamp means forpressing said knife against one side surface of the trough to secure theknife in the trough .
 2. A knife structure comprising a cylindricalrevolver having a trough provided with a bottom surface and two sidesurfaces extending longitudinally of the cylinder, a pusher-part knifesupport disposed in the trough and having a ledge adjacent to the bottomsurface, a knife having a heel surface contacting with the ledge of thepusher-part support to support the knife in the trough and two sidesurfaces one of which contacts with one of the trough side surfaces, thepusher-part support having screw means extending therethrough andengaging the bottom surface of the trough for adjusting said ledgetoward and from the bottom surface of the trough to provide forcorresponding adjustment of the heel surface in contact with said ledge,a clamp in the trough having two oppositely disposed surfaces one ofwhich contacts with the other knife surface, and means engaging theother opposiTely disposed surface of the clamp to secure the clamp inthe trough in order to secure the knife in the trough.
 3. A knifestructure comprising a cylindrical revolver having a trough providedwith a bottom surface and two side surfaces extending longitudinally ofthe cylinder, a plurality of pusher-part knife supports disposed in thetrough and each having a ledge adjacent to the bottom surface, a knifehaving a heel surface contacting with the ledges of the pusher-partsupports to support the knife in the trough and two side surfaces one ofwhich contacts with one of the trough side surfaces, the pusher-partsupports having screw means extending therethrough and engaging thebottom surface of the trough for adjusting said ledges toward and fromthe bottom surface of the trough to provide for corresponding adjustmentof the portions of the heel surface contacting therewith, a plurality ofclamps in the trough each having two oppositely disposed surfaces one ofwhich contacts with the other knife side surface, and means engaging theother oppositely disposed side surfaces of the clamps to secure theclamps in the trough in order to secure the knife in the trough, thesaid one surface of the clamps and the portion of the knife side surfacein contact therewith being tapered with respect to one of the troughside surfaces in order to wedge the knife in the trough.
 4. A knifestructure as defined in claim 3 in which the pusher-part knife supportsare separate from the clamps and are laterally adjustable in the trough.5. A knife structure as defined in claim 1 in which the pusher-partknife support is separate from the clamp means and laterally adjustablein the trough.